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91.
Models of human movement from computational neuroscience provide a starting point for building a system that can produce flexible adaptive movement on a robot. There have been many computational models of human upper limb movement put forward, each attempting to explain one or more of the stereotypical features that characterize such movements. While these models successfully capture some of the features of human movement, they often lack a compelling biological basis for the criteria they choose to optimize. One that does provide such a basis is the minimum variance model (and its extension—task optimization in the presence of signal‐dependent noise). Here, the variance of the hand position at the end of a movement is minimized, given that the control signals on the arm's actuators are subject to random noise with zero mean and variance proportional to the amplitude of the signal. Since large control signals, required to move fast, would have higher amplitude noise, the speed‐accuracy trade‐off emerges as a direct result of the optimization process. We chose to implement a version of this model that would be suitable for the control of a robot arm, using an optimal control scheme based on the discrete‐time linear quadratic regulator. This implementation allowed us to examine the applicability of the minimum variance model to producing humanlike movement. In this paper, we describe our implementation of the minimum variance model, both for point‐to‐point reaching movements and for more complex trajectories involving via points. We also evaluate its performance in producing humanlike movement and show its advantages over other optimization based models (the well‐known minimum jerk and minimum torque‐change models) for the control of a robot arm. © 2005 Wiley Periodicals, Inc. 相似文献
92.
Jan Neumann Cornelia Fermüller Yiannis Aloimonos 《Computer Vision and Image Understanding》2004,96(3):274
The view-independent visualization of 3D scenes is most often based on rendering accurate 3D models or utilizes image-based rendering techniques. To compute the 3D structure of a scene from a moving vision sensor or to use image-based rendering approaches, we need to be able to estimate the motion of the sensor from the recorded image information with high accuracy, a problem that has been well-studied. In this work, we investigate the relationship between camera design and our ability to perform accurate 3D photography, by examining the influence of camera design on the estimation of the motion and structure of a scene from video data. By relating the differential structure of the time varying plenoptic function to different known and new camera designs, we can establish a hierarchy of cameras based upon the stability and complexity of the computations necessary to estimate structure and motion. At the low end of this hierarchy is the standard planar pinhole camera for which the structure from motion problem is non-linear and ill-posed. At the high end is a camera, which we call the full field of view polydioptric camera, for which the motion estimation problem can be solved independently of the depth of the scene which leads to fast and robust algorithms for 3D Photography. In between are multiple view cameras with a large field of view which we have built, as well as omni-directional sensors. 相似文献
93.
94.
Chaniotakis NA Alifragis Y Konstantinidis G Georgakilas A 《Analytical chemistry》2004,76(18):5552-5556
The gallium nitride (GaN) semiconductor is used as the sensing element for the development of a potentiometric anion sensor. The anion recognition mechanism is based on the selective interaction of anions in solution with the epitaxial Ga-face polarity GaN (0001) wurtzite crystal film grown on sapphire. The native GaN crystal is used for the development of an ion blocked sensor. The potential is based on the Volta potential, generated at the semiconductor/solution interface and within the Helmholtz layer, due to specifically adsorbed anions. The selectivity of the sensor is based on the direct interaction of the anionic ligand with the outer electron-defective gallium atoms; thus, it is not dependent on the lipophilicity of the adsorbed charged species. The chemical resistivity of the GaN crystal provides sensors with excellent lifetime, signal stability, and reproducibility. 相似文献
95.
Liu Chunwei Lopez Gonzalez Pavel Leonardo Huang Shuigen Pontikes Yiannis Blanpain Bart Guo Muxing 《Metallurgical and Materials Transactions B》2019,50(3):1260-1268
Metallurgical and Materials Transactions B - Basic oxygen furnace (BOF) steel slag is a major waste of the steelmaking industry. Utilization of BOF slag contributes to the sustainability of the... 相似文献
96.
The Effect of Nutrient Fortification of Sauces on Product Stability,Sensory Properties,and Subsequent Liking by Older Adults 下载免费PDF全文
Roussa Tsikritzi Jianqiu Wang Vanessa J. Collins Victoria J. Allen Yiannis Mavrommatis Paula J. Moynihan Margot A. Gosney Orla B. Kennedy Lisa Methven 《Journal of food science》2015,80(5):S1100-S1110
There are potential nutritional and sensory benefits of adding sauces to hospital meals. The aim of this study was to develop nutrient fortified sauces with acceptable sensory properties suitable for older people at risk of undernutrition. Tomato, gravy, and white sauce were fortified with macro‐ and micronutrients using food ingredients rich in energy and protein as well as vitamin and mineral premixes. Sensory profile was assessed by a trained panel. Hedonic liking of fortified compared with standard sauces was evaluated by healthy older volunteers. The fortified sauces had higher nutritional value than the conventional ones, for example the energy content of the fortified tomato, white sauce, and gravy formulations were increased between 2.5‐ and 4‐fold compared to their control formulations. Healthy older consumers preferred the fortified tomato sauce compared with unfortified. There were no significant differences in liking between the fortified and standard option for gravy. There were limitations in the extent of fortification with protein, potassium, and magnesium, as excessive inclusion resulted in bitterness, undesired flavors, or textural issues. This was particularly marked in the white sauce to the extent that their sensory characteristics were not sufficiently optimized for hedonic testing. It is proposed that the development of fortified sauces is a simple approach to improving energy intake for hospitalized older people, both through the nutrient composition of the sauce itself and due to the benefits of increasing sensorial taste and lubrication in the mouth. 相似文献
97.
This paper describes a model for the assessment and certification of safety-critical programmable electronic systems in the
transportation industries. The proposed model is founded on the significant commonalities between emerging international safety-related
standards in the automotive, railway and aerospace industries. It contains a system development and a safety assessment process
which rationalise and unify the common requirements among the standards in these areas. In addition, it defines an evolutionary
process for the development of the system’s safety case. The safety case process shows how the evidence produced in the progression
of safety assessment can be structured in order to form an overall argument about the safety of the system. We conclude that
it is possible to use this model as the basis of a generic approach to the certification of systems across the transportation
sector. 相似文献
98.
Argiris Tsakiris Yiannis Kourkoutas Vassilis G Dourtoglou Athanasios A Koutinas Constantinos Psarianos Maria Kanellaki 《Journal of the science of food and agriculture》2006,86(4):539-543
Comparative sensory evaluation of wines produced by immobilized cells of Uvaferme 299 on dried raisin berries and free cells using the Saint Denis grape variety and of commercial Greek products (‘Biblia Chora’ rosé wine produced from the Syrah grape variety, ‘Palivos’ and ‘Strofilia’ rosé wines both produced from the Agiorgitiko grape variety) was carried out. Sensory evaluation was conducted twice by 11 tasters previously trained and a method for panel validation was proposed. Subsequently, the wines were evaluated for their aroma intension, aroma complexity, aroma elegance and overall quality. Duncan's multiple range test clearly showed that there were statistically significant differences between wines produced using different grape varieties and fermentation conditions. Linear regression analysis of the results was performed in order to investigate which sensory parameter had a significant effect on the overall quality and it revealed that only aroma elegance affected significantly the overall quality. Wine produced by immobilized cells scored a statistically higher value for its overall quality than the wine produced by free cells. Finally, discriminant sensory evaluation revealed a gooseberry, cherry, mint aroma for ‘Biblia Chora’ wine and a citrus, rose aroma for ‘Strofilia’ and ‘Palivos’ wines. Wines produced using immobilized and free cells were characterized by a fruity, banana‐like aroma, and a herbaceous note was predominant. Copyright © 2005 Society of Chemical Industry 相似文献
99.
100.
Low-level image analysis systems typically detect "points of interest", i.e., areas of natural images that contain corners or edges. Most of the robust and computationally efficient detectors proposed for this task use the autocorrelation matrix of the localized image derivatives. Although the performance of such detectors and their suitability for particular applications has been studied in relevant literature, their behavior under limited input source (image) precision or limited computational or energy resources is largely unknown. All existing frameworks assume that the input image is readily available for processing and that sufficient computational and energy resources exist for the completion of the result. Nevertheless, recent advances in incremental image sensors or compressed sensing, as well as the demand for low-complexity scene analysis in sensor networks now challenge these assumptions. In this paper, we investigate an approach to compute salient points of images incrementally, i.e., the salient point detector can operate with a coarsely quantized input image representation and successively refine the result (the derived salient points) as the image precision is successively refined by the sensor. This has the advantage that the image sensing and the salient point detection can be terminated at any input image precision (e.g., bound set by the sensory equipment or by computation, or by the salient point accuracy required by the application) and the obtained salient points under this precision are readily available. We focus on the popular detector proposed by Harris and Stephens and demonstrate how such an approach can operate when the image samples are refined in a bitwise manner, i.e., the image bitplanes are received one-by-one from the image sensor. We estimate the required energy for image sensing as well as the computation required for the salient point detection based on stochastic source modeling. The computation and energy required by the proposed incremental refinement approach is compared against the conventional salient-point detector realization that operates directly on each source precision and cannot refine the result. Our experiments demonstrate the feasibility of incremental approaches for salient point detection in various classes of natural images. In addition, a first comparison between the results obtained by the intermediate detectors is presented and a novel application for adaptive low-energy image sensing based on points of saliency is presented. 相似文献